Method and apparatus for visually indicating connections between mult-wavelength interfaces and uni-wavelength interfaces

ABSTRACT

A method and apparatus for visually indicating the connections between optical interfaces is provided. The optical interfaces may include multi-wavelength optical interfaces and uni-wavelength optical interfaces. The optical interfaces may reside within optical nodes contained within an optical network.

RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.14/920,276 filed Oct. 22, 2015, which is a continuation of U.S.application Ser. No. 14/014,493, filed Aug. 30, 2013. The specificationof the present invention is substantially the same as that of the parentapplication. The “Related Application” paragraph has been revised toinclude a specific reference to the parent application. Thespecification of the present invention contains no new subject matter.

BACKGROUND

In a Wavelength Division Multiplexed (WDM) optical communication node,optical connections are configured between a plurality of uni-wavelengthports and a plurality of multi-wavelength ports. In prior-art opticalnodes, there was no visual indication of which uni-wavelength ports areconnected to which multi-wavelength ports, thus leading to confusion andunintended disruptions in service during maintenance periods.

SUMMARY

A method and corresponding apparatus for visually indicating theconnections between multi-wavelength interfaces and uni-wavelengthinterfaces is presented. The apparatus comprises a firstmulti-wavelength interface with a first multi-wavelength interfaceindicator capable of indicating a first state, at least a secondmulti-wavelength interface with a second multi-wavelength interfaceindicator capable of indicating a second state, and at least oneuni-wavelength interface with a uni-wavelength interface indicatorcapable of indicating the first state and the second state. A connectionbetween the at least one uni-wavelength interface and the firstmulti-wavelength interface is indicated by the uni-wavelength interfaceindicator indicating the first state. A connection between the at leastone uni-wavelength interface and the at least second multi-wavelengthinterface is indicated by the uni-wavelength interface indicatorindicating the second state.

The apparatus may be contained within an optical node within an opticalnetwork. In such a case, the apparatus may be partitioned acrossmultiple circuit packs, or it may reside within a single circuit pack,or a single mechanical structure (such as an electrically poweredenclosure).

The multi-wavelength interface indicators may be passive indicators(requiring no electrical power), or they may be active indicators(requiring electrical power).

The multi-wavelength and uni-wavelength interface indicators maycomprise of multi-color light sources. Each multi-color light source maybe implemented with multiple light emitting diodes (LEDs) within asingle mechanical package, such as commercially available bi-color LEDs(with two LEDs) or tri-color LEDs (with three LEDs). Therefore, thefirst multi-wavelength interface indicator may include a first lightemitting diode, and the second multi-wavelength interface indicator mayinclude a second light emitting diode, and the uni-wavelength interfaceindicator may include a third light emitting diode. For this case, thefirst state may be indicated with a first color, and the second statemay be indicated with a second color.

Alternatively, the first multi-wavelength interface indicator maycomprise a first alphanumeric display, and the second multi-wavelengthinterface indicator may comprise a second alphanumeric display, and theuni-wavelength interface indicator may comprise a third alphanumericdisplay. For this case, the first state may be indicated with a firstletter or numeral, and the second state may be indicated with a secondletter or numeral.

Alternatively, the first multi-wavelength interface indicator mayinclude a first passive indicator, and the second multi-wavelengthinterface indicator may include a second passive indicator, and theuni-wavelength interface indicator may include an active indicator.

A connection between the at least one uni-wavelength interface and thefirst multi-wavelength interface, and the at least one uni-wavelengthinterface the at least second multi-wavelength interface may beindicated by the uni-wavelength interface indicator alternating (cyclingor sequencing) between the first state and the second state.

The apparatus may further comprise at least a third multi-wavelengthinterface with a third multi-wavelength interface indicator capable ofindicating a third state. For this case, the uni-wavelength interfaceindicator is further capable of indicating the third state. A connectionbetween the at least one uni-wavelength interface and the firstmulti-wavelength interface, and the at least one uni-wavelengthinterface the at least second multi-wavelength interface, and the atleast one uni-wavelength interface and the at least thirdmulti-wavelength interface is indicated by the uni-wavelength interfaceindicator cycling (sequencing) from the first state, to the secondstate, to the third state, and back to the first state.

The method for indicating connections between interfaces comprisesindicating a first state with a first interface indicator of a firstinterface, indicating a second state with a second interface indicatorof a second interface, and indicating the first state and the secondstate with a third interface indicator of a third interface. The thirdinterface indicator indicates a connection between the third interfaceand the first interface by indicating the first state. The thirdinterface indicator indicates a connection between the third interfaceand the second interface by indicating the second state.

In the method, the first interface indicator may include a first lightemitting diode, and the second interface indicator may include a secondlight emitting diode, and the third interface indicator may include athird light emitting diode.

Alternatively, in the method, the first interface indicator may comprisea first alphanumeric display, and the second interface indicator maycomprise a second alphanumeric display, and the third interfaceindicator may comprise a third alphanumeric display.

Alternatively, in the method, the first interface indicator may includea first passive indicator, and the second interface indicator mayinclude a second passive indicator, and the third interface indicatormay include an active indicator of some type (multi-color oralphanumeric, for example).

Alternatively, in the method, the first interface indicator may compriseat least two light emitting diodes, and the second interface indicatormay comprise at least two light emitting diodes, and the third interfaceindicator may comprise at least two emitting diodes.

Within the method, the first state may be indicated by a first color andthe second state may be indicated by a second color.

Also, within the method, a connection between the third interface andthe first interface, and the third interface and the second interfacemay be indicated by the third interface indicator alternating betweenthe first state and the second state.

Within the method, the first interface and the second interface may bemulti-wavelength interfaces, while the third interface may be auni-wavelength interface.

Another embodiment of the invention comprises an optical node comprisinga first multi-wavelength interface with a first multi-wavelengthinterface indicator capable of illuminating with a first color, at leasta second multi-wavelength interface with a second multi-wavelengthinterface indicator capable of illuminating with a second color, and atleast one uni-wavelength interface with a uni-wavelength interfaceindicator capable of illuminating with the first color and the secondcolor. The optical node supports connections between the at least oneuni-wavelength interface and the first multi-wavelength interface, andbetween the at least one uni-wavelength interface and the at leastsecond multi-wavelength interface. These connections are referred to asintra-node connections. An intra-node connection between the at leastone uni-wavelength interface and the first multi-wavelength interface isindicated by illuminating the uni-wavelength interface indicator withthe first color, and a an intra-node connection between the at least oneuni-wavelength interface and the second multi-wavelength interface isindicated by illuminating the uni-wavelength interface indicator withthe second color.

The optical node is also capable of establishing connections to and froma second node within an optical network. These connections are referredto as inter-node connections. More specifically, an inter-nodeconnection may be established between the at least one uni-wavelengthinterface (within the node) and a second uni-wavelength interface of asecond optical node through the first multi-wavelength interface. Aproblem with the inter-node connection may be indicated by theuni-wavelength interface indicator by alternating between the firstcolor and no color. That is to say, a problem with the inter-nodeconnection may be indicated by the uni-wavelength interface indicator byturning the indicator on and off.

The optical node is capable of establishing a first inter-nodeconnection between the at least one uni-wavelength interface and asecond uni-wavelength interface of a second optical node through thefirst multi-wavelength interface. Additionally, the optical node iscapable of establishing at least a second inter-node connection betweenthe at least one uni-wavelength interface and a third uni-wavelengthinterface of a third optical node through the at least secondmulti-wavelength interface. For this broadcasting scenario, theuni-wavelength interface indicator indicates the first inter-nodeconnection and the at least second inter-node connection by alternatingbetween the first color during a first time period and the second colorduring a second time period. If there is a problem with the firstinter-node connection, the problem may be indicated by theuni-wavelength interface indicator by alternating between the firstcolor and no color during the first time period.

The optical node may further comprise at least one ROADM circuit packcomprising at least the first multi-wavelength interface and the firstmulti-wavelength interface indicator. The ROADM circuit pack may furthercomprise the at least a second multi-wavelength interface and the secondmulti-wavelength interface indicator.

The optical node may further comprise at least one multiplexer anddemultiplexer circuit pack comprising the at least one uni-wavelengthinterface and the uni-wavelength interface indicator. The multiplexerand demultiplexer circuit pack may further comprise a front panel and aprinted circuit board. The front panel may comprise at least one opticalconnector for the at least one uni-wavelength interface. The printedcircuit board may comprise the uni-wavelength interface indicator forthe at least one uni-wavelength interface. The printed circuit board maybe located directly behind the front panel so that the at least oneoptical connector extends through the printed circuit board.

The optical node may further comprise at least one optical transponder.The optical transponder may have a second uni-wavelength interfaceindicator whose state matches the state of the uni-wavelength indicator.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingembodiments of the present invention.

FIG. 1 is an illustration of an optical network containing four opticalnodes in an example embodiment of the present invention.

FIG. 2 is an illustration of an optical node containing three ROADMs inan example embodiment of the present invention.

FIG. 3 is an illustration of a ROADM containing three multi-wavelengthinterfaces in an example embodiment of the present invention.

FIG. 4 is an illustration of an optical node containing a ROADM, amultiplexing and de-multiplexing device, and three transponders in anexample embodiment of the present invention.

FIG. 5A is an illustration of the construction of a multiplexing andde-multiplexing circuit pack in an example embodiment of the presentinvention.

FIG. 5B is a further illustration of the construction of a multiplexingand de-multiplexing circuit pack in an example embodiment of the presentinvention.

FIG. 5C is a further illustration of the construction of a multiplexingand de-multiplexing circuit pack in an example embodiment of the presentinvention.

DETAILED DESCRIPTION

A description of example embodiments of the invention follows.

FIG. 1 is an illustration of an optical network 100 containing fouroptical nodes 110, 120, 130, and 140. Each optical node contains two orthree multi-wavelength interfaces 112 a-c, 122 a-b, 132 a-c, and 142 a-cused to interconnect each node to other like nodes. Additionally, eachoptical node contains a plurality of uni-wavelength interfaces 111 a-c,121 a-c, 131 a-c, and 141 a-c. A multi-wavelength interface is capableof supporting one or more wavelengths using wavelength divisionmultiplexing, while a uni-wavelength interface is capable of supportingonly a single optical wavelength. Each optical node is connected to twoor three other optical nodes via optical fiber cables 150 a-e thatinterconnect the multi-wavelength interfaces of the nodes. Eachuni-wavelength interface is used to add and drop wavelengths to and fromthe fiber that interconnects the nodes. Within an optical node 110, 120,130, and 140, circuitry is provided that allows a wavelength from aparticular uni-wavelength interface (an add port) to be directed to anyof the associated multi-wavelength interfaces of the node. Similarly,within an optical node 110, 120, 130, and 140, circuitry is providedthat allows a wavelength to be directed to a uni-wavelength interface (adrop port) from any of the associated multi-wavelength interfaces of thenode. Often such uni-wavelength interfaces are referred to asdirectionless uni-wavelength interfaces.

Within each optical node, a multi-wavelength interface indicator (114a-c, 124 a-b, 134 a-c, and 144 a-c) is associated with eachmulti-wavelength interface, and a uni-wavelength indicator (113 a-c, 123a-c, 133 a-c, and 143 a-c) is associated with each uni-wavelengthinterface. Each multi-wavelength interface indicator and eachuni-wavelength indicator is preferably located adjacent to thecorresponding interface or port, as shown in FIG. 1. The interfaceindicators are used to visually indicate the connections between eachmulti-wavelength interface and each uni-wavelength interface. In oneexample embodiment, each multi-wavelength interface indicator and eachuni-wavelength interface indicator comprises a multi-color light source,capable of generating any number of colors. Within a given node, eachmulti-wavelength interface indicator 114 a-c, 124 a-b, 134 a-c, and 144a-c is configured to illuminate with a visual color that is distinctfrom all other multi-wavelength interface indicators. If there are nmulti-wavelength interfaces within a given optical node, then n distinctcolors are required (color 1, color 2, color 3 . . . and color n). Forinstance, for an optical node with three multi-wavelength interfaces(like nodes 110 and 130), multi-wavelength interface 1 may have itsassociated multi-wavelength interface indicator illuminated with thecolor green (color 1), while multi-wavelength interfaces 2 and 3 mayhave their associated multi-wavelength interface indicators illuminatedwith the colors blue (color 2) and yellow (color 3) respectively. So forexample within node 110, multi-wavelength interface indicator 114 aassociated with multi-wavelength interface 112 a would be illuminatedgreen, while multi-wavelength interface indicators 114 b and 114 cassociated with multi-wavelength interfaces 112 b and 112 c respectivelywould be illuminated with the colors blue and yellow respectively.

Both the multi-wavelength interfaces and the uni-wavelength interfacesare bidirectional optical interfaces, typically implemented with twofiber optical connectors—one for exiting signal(s), and one for enteringsignal(s). Therefore, for every optical wavelength entering auni-wavelength interface, there is typically an associated companionwavelength of the same frequency exiting the same uni-wavelengthinterface. Similarly, for a set of wavelengths entering amulti-wavelength interface, there is typically an associated set ofcompanion wavelengths of the same optical frequencies exiting the samemulti-wavelength interface. When a given wavelength is added to auni-wavelength interface of a given node, the given node is configuredto direct the added outgoing wavelength to one of the n multi-wavelengthinterfaces of the associated node. In a like manner, the given node isconfigured to direct the outgoing wavelength's companion incomingwavelength from the same multi-wavelength interface to the sameuni-wavelength interface. In this manner, it can be stated that aconnection is made between the given uni-wavelength interface and thegiven multi-wavelength interface. A connection that connects awavelength between interfaces within an optical node may be called anintra-node connection. Once the connection between the uni-wavelengthinterface and the multi-wavelength interface is completed, theuni-wavelength interface indicator associated with the uni-wavelengthinterface is used to indicate that it is connected to the particularmulti-wavelength interface. When each interface indicator comprises amulti-color light source, the color of the uni-wavelength interfaceindicator of the uni-wavelength interface is illuminated with the samecolor as that of the multi-wavelength interface indicator of themulti-wavelength interface that it is connected to (i.e., the color ofthe indicator of the uni-wavelength interface is set to match the colorof the interface indicator of the multi-wavelength interface). Forinstance, if a given uni-wavelength interface is connected tomulti-wavelength interface 1 whose associated color is color 1, then theuni-wavelength interface indictor of the given uni-wavelength interfaceis also set to color 1.

Within an optical network, a wavelength may be connected from a firstuni-wavelength interface of a first node to a second uni-wavelengthinterface of a second node. Such a connection may be called aninter-node connection. Multiple intra-node connections (within multiplenodes) may be required in order to establish a single inter-nodeconnection. As a network illustration, assume that a wavelength i isadded to uni-wavelength interface 111 a of node 110. Further assume thatthe wavelength's network destination is uni-wavelength interface 131 cin node 130. For this case, an inter-node connection must be establishedbetween interface 111 a and interface 131 c. Node 110 is configured toconnect wavelength i from uni-wavelength interface 111 a tomulti-wavelength interface 112 a. Node 110 is additionally configured toilluminate the uni-wavelength interface indictor 113 a of theuni-wavelength interface 111 a to the same color as the multi-wavelengthinterface indicator 114 a of multi-wavelength interface 112 a. Node 140is configured to connect wavelength i from multi-wavelength interface142 b to multi-wavelength interface 142 a. Node 130 is configured toconnect wavelength i from multi-wavelength interface 132 a touni-wavelength interface 131 c. Node 130 is additionally configured toilluminate the uni-wavelength interface indictor 133 c of theuni-wavelength interface 131 c with the same color as themulti-wavelength interface indicator 134 a of multi-wavelength interface132 a.

Continuing the previous network illustration further, assume that theoptical fiber 150 e between nodes 140 and 130 gets cut, so that nowavelengths can traverse between network node 140 and network node 130via fiber 150 e. Once the network discovers the failure, network nodes110 and 130 are reconfigured as follows. Node 110 is configured todisconnect wavelength i from multi-wavelength interface 112 a. Node 110is further configured to connect wavelength i from uni-wavelengthinterface 111 a to multi-wavelength interface 112 c. Node 110 isadditionally configured to illuminate the uni-wavelength interfaceindictor 113 a of the uni-wavelength interface 111 a to the same coloras the multi-wavelength interface indicator 114 c of multi-wavelengthinterface 112 c. Node 130 is configured to disconnect wavelength i frommulti-wavelength interface 132 a. Node 130 is further configured toconnect wavelength i from multi-wavelength interface 132 c touni-wavelength interface 131 c. Node 130 is additionally configured toilluminate the uni-wavelength interface indictor 133 c of theuni-wavelength interface 131 c with the same color as themulti-wavelength interface indicator 134 c of multi-wavelength interface132 c.

In general the multi-wavelength interface indicators and uni-wavelengthinterface indicators have one or more states associated with them. Thestates associated with a multi-color interface indicator are representedby the n colors in which the multi-color indicator displays. For thiscase, color 1 is a state, color 2 is a state, and color n is a state,and there are n total color states that an indicator can assume. Aalphanumeric display may be used as an interface indicator. The statesassociated with a alphanumeric display are the various numbers orcharacters in which the display can display. In normal operation, themulti-wavelength interface indicators for the multi-wavelengthinterfaces may have a permanent state assigned to them. For instance, ifmulti-wavelength interface j is assigned the color green, themulti-wavelength interface indicator associated with multi-wavelengthinterface j will be displaying a steady state green color on a more orless permanent basis. Because of this, for simple implementations, astatic multi-wavelength interface indicator (such as a colored stickeror colored tag) could be used as the indicator for multi-wavelengthinterfaces. A static multi-wavelength interface indicator like a coloredsticker or colored tag is passive and would not require electricalpower.

An interface indicator can have additional states beyond the steadystate used to indicate the connection between a uni-wavelength interfaceand a multi-wavelength interface. For instance, a given indicator mayalso assume a blinking state, wherein—for the case of a multi-colorlight source—the indicator may blink on and off (i.e., color and nocolor) at a fast but visible rate in a continuous manner. Such a statecould be used to indicate that there is a problem associated with theconnection. For instance, when a fiber cut occurs that disrupts the flowof wavelengths through a multi-wavelength interface, the associatedmulti-wavelength interface indicator may blink on and off at a visiblerate in order to visual indicate the problem. In the previouslydiscussed network illustration, once the fiber cut to fiber 150 e isdetected and reported, and before a restoration takes place, theuni-wavelength interface indicator 113 a in node 110, and theuni-wavelength interface indicator 133 c in node 130 could both visiblyblink. For this case, indicator 113 a may blink on and off with thecolor associated with multi-wavelength interface indicator 114 a, andindicator 133 c may blink on and off with the color associated withmulti-wavelength interface indicator 134 a.

Beyond fiber cuts, a blinking state could be used to indicate anyproblem that affects a connection between two interfaces within anetwork. For instance, if there was fiber connectivity between auni-wavelength interface in one node and an uni-wavelength interface inanother node, but for protocol reasons (or some other reason)information was not flowing between the two uni-wavelength interfaces,the interface indicators associated with the two uni-wavelengthinterfaces may be configured to blink on and off (i.e., color followedby no color). Once the problem is cleared—and information flows betweenthe two uni-wavelength interfaces—the blinking would be stopped, and theuni-wavelength interface indicators of the two uni-wavelength interfaceswould assume their non-blinking steady state values associated with themulti-wavelength interface that they are connected to locally (via anintra-node connection). For the case wherein a multi-color light sourceis used as an indicator for the uni-wavelength interface, once theproblem is cleared, the indicator would be illuminated in a steady statewith the color associated with the multi-wavelength interface indicatorof the multi-wavelength interface that it is locally (within the node)connected to.

In one embodiment, when an inter-node connection between auni-wavelength interface in one node and a uni-wavelength interface inanother node has a problem such that information does not flow betweenthe two uni-wavelength interfaces, the uni-wavelength interfaceindicators on the uni-wavelength interfaces will blink, but themulti-wavelength interface indicators on the multi-wavelength interfacesthat they are locally connected to (via intra-node connections) will notblink. An exception to this may be for the case where there is a directproblem with a given multi-wavelength interface. For instance, for aconnection from interface 111 a to 131 c through node 140, if the fiber150 e attached to multi-wavelength interface 132 a is cut, such that theconnection between interface 111 a and interface 131 c is disrupted, themulti-wavelength interface indicator 134 a may optionally be blinked onand off, since all connections through interface 132 a are no longerpossible. For this case, the multi-wavelength interface indicator 114 aof multi-wavelength interface 112 a in node 110 does not blink on andoff, since connections to node 140 are still possible throughmulti-wavelength interface 112 a.

At least one additional state (color) may be used beyond those needed tosupport the n multi-wavelength interfaces within an optical node. Theadditional state (color) may be used to indicate that a givenuni-wavelength interface is not connected to any of the multi-wavelengthinterfaces within the optical node. If multi-color light sources areused as interface indicators, if no connection is made between a givenuni-wavelength interface and any of the multi-wavelength interfaces, theuni-wavelength interface indicator of the given uni-wavelength interfacemay be illuminated with a color different than any of the colorsassociated with any of the multi-wavelength interfaces within the node.Optionally, if no connection is made between a given uni-wavelengthinterface and any of the multi-wavelength interfaces, the uni-wavelengthinterface indicator of the given uni-wavelength interface may beilluminated with a color different than any of the colors associatedwith any of the multi-wavelength interfaces within the node, and theuni-wavelength interface indicator of the uni-wavelength interface mayadditionally be blinked on and off at a visible rate. As yet anotheroption, if no connection is made between a given uni-wavelengthinterface and any of the multi-wavelength interfaces, the uni-wavelengthinterface indicator of the given uni-wavelength interface may beextinguished (i.e., turned off so that no color is illuminated).

The optical nodes 110, 120, 130, and 140 may be constructed in such away that a given uni-wavelength interface can broadcast its associatedwavelength to more than one multi-wavelength interface. This type ofoperation would be especially useful for video distributionapplications. For this case, the uni-wavelength interface indicatorassociated with the uni-wavelength interface whose wavelength is beingbroadcasted to multiple multi-wavelength interfaces may cycle through(sequence through) the states of the multi-wavelength interfaceindicators of the multi-wavelength interfaces that it is broadcastingto. More specifically, when a connection is between a uni-wavelengthinterface and a first and at least a second multi-wavelength interface,the uni-wavelength interface indicator associated with theuni-wavelength interface cycles through the indicator states of themulti-wavelength interface indicators of the first multi-wavelengthinterface and the at least second multi-wavelength interface. As anexample, if uni-wavelength interface 111 a is broadcasting to bothmulti-wavelength interface 112 a and 112 b, and the indicator statesassociated with the multi-wavelength interface indicators 114 a and 114b are the colors blue and green respectively, then the uni-wavelengthinterface indicator 113 a of uni-wavelength interface 111 a will cycle(sequence) through the colors blue and green at a slow and visible rate.In other words, the interface indicator 113 a will alternate betweenblue and green.

In more general terms, the invention may be described as an apparatuscomprising a first multi-wavelength interface with a firstmulti-wavelength interface indicator capable of indicating a firststate, at least a second multi-wavelength interface with a secondmulti-wavelength interface indicator capable of indicating a secondstate, and at least one uni-wavelength interface with a uni-wavelengthinterface indicator capable of indicating the first state and the secondstate. A connection between the at least one uni-wavelength interfaceand the first multi-wavelength interface is indicated by theuni-wavelength interface indicator indicating the first state. Aconnection between the at least one uni-wavelength interface and the atleast second multi-wavelength interface is indicated by theuni-wavelength interface indicator indicating the second state.

The apparatus may further comprise at least a third multi-wavelengthinterface with a third multi-wavelength interface indicator capable ofindicating a third state. For this case, the uni-wavelength interfaceindicator is further capable of indicating the third state. A connectionbetween the at least one uni-wavelength interface and the firstmulti-wavelength interface, and the at least one uni-wavelengthinterface the at least second multi-wavelength interface, and the atleast one uni-wavelength interface the at least third multi-wavelengthinterface is indicated by the uni-wavelength interface indicator cycling(sequencing) from the first state, to the second state, to the thirdstate, and back to the first state.

The uni-wavelength indicator and the multi-wavelength indicators may bemulti-color light sources (such as multiple LEDs), or alphanumericdisplays.

In an optical network, when using multi-color light sources as interfaceindicators, when a first uni-wavelength interface of a first opticalnode is configured to be connected to a second uni-wavelength interfaceof a second optical node through a first multi-wavelength interface ofthe first optical node, and additionally when the first uni-wavelengthinterface of a first optical node is configured to be connected to athird uni-wavelength interface of a third optical node through a secondmulti-wavelength interface of the first optical node, the color of theuni-wavelength interface indicator of the first uni-wavelength interfaceis configured to visibly cycle through the two colors of themulti-wavelength interface indicators of the first multi-wavelengthinterface and the second multi-wavelength interface. If there is aproblem with the connection between the first uni-wavelength interfaceand the second uni-wavelength interface, the uni-wavelength interfaceindicator of the first uni-wavelength interface is configured to visiblyslowly cycle through the two colors of the multi-wavelength interfaceindicators of the first multi-wavelength interface and the secondmulti-wavelength interface, and the indicator of the firstuni-wavelength interface is rapidly but visibly blinked on and off whendisplaying the color of the multi-wavelength interface indicator of thefirst multi-wavelength interface during the cycle. In other terms, thecycle may consist of multiple time periods. For instance, when cycling(sequencing) through two colors of two multi-wavelength interfaces, twotime periods can be defined—the time period in which the first color(state) is displayed, and the time period in which the second color(state) is displayed. In one embodiment each time period may last 2seconds, so that the first color (state) is displayed for 2 seconds,followed by the second color (state) being displayed for 2 seconds,followed by the first color (state) being displayed for 2 seconds, etc.For this case, when there is a problem with say the first connection(associated with the first state/color), the first color (state) will berapidly but visibly blinked on and off for 2 seconds (perhaps on and offonce every half second, for example), followed by 2 seconds in which thesecond color (state) is steadily displayed, followed by 2 seconds of thefirst color (state) being rapidly blinked on and off, followed by 2seconds in which the second color (state) is steadily displayed, etc.

In summary, when using multi-color light sources as interface indicatorswithin an optical node, the multi-wavelength interface indicator ofmulti-wavelength interface i is illuminated with color i, wherein iranges from 1 to n, wherein n is the total number of multi-wavelengthinterfaces within the node. When a given uni-wavelength interface withinthe optical node is connected to multi-wavelength interface i, theuni-wavelength interface indicator of the uni-wavelength interface isilluminated with the color i. If a uni-wavelength interface is connectedto j number of multi-wavelength interfaces, the uni-wavelength interfaceindicator of that uni-wavelength interface cycles (sequences) throughthe j colors associated with the j number of multi-wavelengthinterfaces.

In an optical network, when using alphanumeric displays as interfaceindicators, the alphanumeric display used as the first multi-wavelengthinterface indicator will be assigned a first alphanumeric character set(letter(s)/number(s)), and the alphanumeric display used as the secondmulti-wavelength interface indicator will be assigned a secondalphanumeric character set (letter(s)/number(s)). When a firstuni-wavelength interface of a first optical node is configured to beconnected to a second uni-wavelength interface of a second optical nodethrough the first multi-wavelength interface of the first optical node,and additionally when the first uni-wavelength interface of a firstoptical node is configured to be connected to a third uni-wavelengthinterface of a third optical node through the second multi-wavelengthinterface of the first optical node, the alphanumeric display of theuni-wavelength interface indicator of the first uni-wavelength interfaceis configured to visibly alternate between the first alphanumericcharacter set and the second alphanumeric character set of themulti-wavelength interface indicators of the first multi-wavelengthinterface and the second multi-wavelength interface. If there is aproblem with the connection between the first uni-wavelength interfaceand the second uni-wavelength interface, the uni-wavelength interfaceindicator of the first uni-wavelength interface is configured to visiblyalternate between the first alphanumeric character set and the secondalphanumeric character set, and the indicator of the firstuni-wavelength interface is rapidly but visibly blinked on and off whendisplaying the first alphanumeric character set. In other terms, thecycle may consist of multiple time periods. For instance, whenalternating between the first alphanumeric character set and the secondalphanumeric character set of two multi-wavelength interfaces, two timeperiods can be defined—the time period in which the first alphanumericcharacter set (state) is displayed, and the time period in which thesecond alphanumeric character set (state) is displayed. In oneembodiment each time period may last 2 seconds, so that the firstalphanumeric character set (state) is displayed for 2 seconds, followedby the second alphanumeric character set (state) being displayed for 2seconds, followed by the first alphanumeric character set (state) beingdisplayed for 2 seconds, etc. For this case, when there is a problemwith say the first connection (associated with the first state), thefirst alphanumeric character set will be rapidly but visibly blinked onand off for 2 seconds (perhaps on and off once every half second, forexample), followed by 2 seconds in which the second alphanumericcharacter set is steadily displayed, followed by 2 seconds of the firstalphanumeric character set being rapidly blinked on and off, followed by2 seconds in which the second alphanumeric character set is steadilydisplayed, etc.

The interface indicators provide the network operator a quick an easyvisual indication of the routing of all added and dropped wavelengths ata given node. This may be useful information when configuring or troubleshooting a system, and may prevent network operator errors. Forinstance, if a given multi-wavelength interface indicator of a givenmulti-wavelength interface is illuminated with a steady state 1, andthere are also uni-wavelength indicators of uni-wavelength interfacesbeing illuminated with a steady state 1, then the network operator knowsthat he cannot disturb the optical link (fibers) associated with thegiven multi-wavelength interface.

Each multi-wavelength interface and each uni-wavelength interface willhave an optical connector associated with it. For the uni-wavelengthinterface, the optical connector is used to connect the uni-wavelengthinterface to an optical transponder using optical fiber. (An opticaltransponder is a device that generates and terminates an opticalwavelength.) For the multi-wavelength interface, the optical connectoris used to connect the multi-wavelength interface to another opticalnode within the network using optical fiber. The uni-wavelengthinterface indicator for the uni-wavelength interface may preferably belocated adjacent to the optical connector associated with theuni-wavelength interface. Similarly, the multi-wavelength interfaceindicator for the multi-wavelength interface may preferably be locatedadjacent to the optical connector associated with multi-wavelengthinterface.

The uni-wavelength interfaces 111 a-c, 121 a-c, 131 a-c, and 141 a-c maybe so called colored uni-wavelength interfaces, or they may be so calledcolorless uni-wavelength interfaces. Each colored uni-wavelengthinterface has a specific wavelength assigned to it, while a colorlessuni-wavelength interface can utilize any wavelength used within itsassociated optical network.

Each optical node 110, 120, 130, and 140 may be constructed using one ormore Reconfigurable Optical Add/Drop Multiplexer (ROADM) circuit packs.Such a node 200 is depicted in FIG. 2. Each of the three ROADM circuitpacks 210, 220, and 230 provides a single multi-wavelength interface212, 222, and 232. Associated with each multi-wavelength interface is amulti-wavelength interface indicator 214, 224, and 234. Each ROADMcircuit pack additionally contains a plurality of express interfaces 213a-c, 223 a-c, and 233 a-c, used to interconnect each ROADM circuit packto all other ROADM circuit packs, and also used to connect each ROADMcircuit pack to a directionless add/drop circuit pack 250. Thedirectionless add/drop circuit pack 250 contains the necessary circuitryneeded to drop wavelengths from any of the three multi-wavelengthinterfaces 212, 222, and 232, and also contains the necessary circuitryneeded to add wavelengths to any of the three multi-wavelengthinterfaces. For instance, in one embodiment, each ROADM circuit packforwards all the wavelengths it receives from its multi-wavelengthinterface to the directionless add/drop circuit pack using the expressinterface connected to the directionless add/drop circuit pack. Theadd/drop circuit pack then forwards selected wavelengths to itsdirectionless uni-wavelength interfaces 251 a-c. In the “add” direction,the directionless add/drop circuit pack takes in added wavelengths fromits uni-wavelength interfaces 251 a-c, and then directs the addedwavelengths to one or more of its express interfaces 253 a-c, dependingupon which multi-wavelength interface 212, 222, 232 the addedwavelengths must be added to. In the example node 200, theuni-wavelength interface indicators 255 a-c for the uni-wavelengthinterfaces 251 a-c are located on the directionless add/drop circuitpack.

The three ROADM circuit packs and the directionless add/drop circuitpack may all be plugged into an equipment chassis. Alternatively, thethree ROADM circuit packs and the directionless add/drop circuit packmay be plugged into multiple equipment chassis. Additionally, one ormore ROADM circuit packs 210, 220, and 230 may be combined so as tocreate at least one circuit pack with at least two multi-wavelengthinterfaces. Additionally, one or more ROADM circuit packs 210, 220, and230 may be combined with the directionless add/drop circuit pack.Additionally, an optical node may contain more than one directionlessadd/drop circuit pack.

Although not explicitly shown in FIG. 2, the express interfaces may alsohave corresponding interface indicators. The states of the expressinterface indicators on the directionless add/drop circuit pack would beconfigured to match the states of the corresponding multi-wavelengthinterface indicators of the multi-wavelength interfaces on thecorresponding ROADM circuit pack. For instance, the express interfaceindicator for express interface 253 a would be set to match the state ofthe multi-wavelength interface indicator 214, while the expressinterface indicator for express interface 253 b would be set to matchthe state of the multi-wavelength interface indicator 224.

FIG. 3 shows a ROADM circuit pack 300 that can be plugged into anequipment chassis (not shown). The ROADM circuit pack 300 contains threemulti-wavelength interfaces 312 a-c instead of one. The ROADM circuitpack 300 also has a multi-wavelength interface indicator 314 a-cassociated with each of its multi-wavelength interfaces 312 a-c. TheROADM circuit pack additionally has a plurality of directionlessuni-wavelength add drop ports 311 a-c built into it, each having auni-wavelength interface indicator 313 a-c. In some implementations, theROADM circuit pack may only have a single uni-wavelength interface builtinto it. Each uni-wavelength interface 311 a-c built into the ROADMcircuit pack 300 has a uni-wavelength interface indicator 313 a-cassociated with it that is located on the ROADM circuit pack. In oneembodiment, the ROADM circuit pack 300 may require transponders that arelocated external to the ROADM circuit pack 300. In another embodiment,the ROADM circuit pack may have some number of transponders built intothe circuit pack. For this later case, some number of uni-wavelengthinterfaces may be located within the internals of the ROADM circuitpack, and would not be visible outside of the ROADM circuit pack.

The ROADM circuit packs 210, 220, 230, and 300 contain at least onemulti-wavelength interface, and may use multi-color light sources fortheir multi-wavelength interface indicators. Each multi-wavelengthinterface indicator i of each multi-wavelength interface on a ROADMcircuit pack is illuminated with color i, wherein i ranges from 1 to n,wherein n is the total number of multi-wavelength interfaces in theoptical node. The multi-wavelength interface indicator of the at leastone multi-wavelength interface on the ROADM is illuminated with thecolor i associated with its multi-wavelength interface. When a givenuni-wavelength interface is connected to multi-wavelength interface i,the uni-wavelength interface indicator of the uni-wavelength interfaceis illuminated with the color i. If a uni-wavelength interface isconnected to j number of multi-wavelength interfaces, the uni-wavelengthinterface indicator of that uni-wavelength interface cycles through thej colors associated with the j number of multi-wavelength interfaces.

FIG. 4 depicts an optical node 400 comprising of a ROADM circuit pack430 containing three multi-wavelength interfaces 432 a-c—each with amulti-wavelength interface indicator 434 a-c, a multiplexer anddemultiplexer circuit pack 440 containing a plurality of directionlessuni-wavelength interfaces 441 a-c—each with a uni-wavelength indicator443 a-c, and a plurality of transponders 460 a-c.

In the add direction, the transponders 460 a-c generate a plurality ofwavelengths that are forwarded to the multiplexer and demultiplexercircuit pack 440 via optical fibers 450 a-c. The multiplexer anddemultiplexer circuit pack multiplexes the plurality of wavelengthstogether to form a composite Wavelength Division Multiplexed (WDM)signal that is then forwarded to the ROADM circuit pack 430 via opticalfiber 455. At each output multi-wavelength interface 432 a-c of theROADM circuit pack, wavelengths selected from the WDM signal from themultiplexer and demultiplexer circuit pack are combined with wavelengthsselected from the input interfaces of the other two multi-wavelengthinterfaces 432 a-c to form a composite WDM stream for transmission.

In the drop direction, a composite WDM signal containing selectedwavelengths from the input of each multi-wavelength interface 432 a-c ofthe ROADM circuit pack 430 are forwarded to the multiplexer anddemultiplexer circuit pack 440 via fiber 455 (which may be actually twooptical fibers—one for each direction). The multiplexer anddemultiplexer circuit pack de-multiplexes the WDM signal and forwardsone wavelength to each of the transponders 460 a-c via fibers 450 a-c.(Each fiber 450 a-c may be actually two fibers—one for each direction.)

The uni-wavelength interface indicators 443 a-c for the directionlessuni-wavelength interfaces 441 a-c are located on the multiplexer anddemultiplexer circuit pack 440, while the multi-wavelength interfaceindicators 434 a-c for the multi-wavelength interfaces are located onthe ROADM circuit pack.

The multiplexer and demultiplexer circuit pack 440 may further comprisea front panel and optical connectors for each uni-wavelength interface.Such a multiplexer and demultiplexer circuit pack 500 is illustrated inFIG. 5A, FIG. 5B, and FIG. 5C. FIG. 5A illustrates a multiplexer anddemultiplexer circuit pack 500 comprising a front panel 510 and aprinted circuit board 520. The front panel 510 further comprises opticalconnectors 511 a-1, and windows 513 a-1 for the uni-wavelength interfaceindicators located on the printed circuit board. The front panel alsocomprises an optical connector 515 used to optically connect themultiplexer/demultiplexer circuit pack to the ROADM circuit pack, and acorresponding window 514 for a summary indicator 524 (located on theprinted circuit board). The printed circuit board 520 comprises theuni-wavelength interface indicators 523 a-1, and a summary indicator524. The printed circuit board 520 also contains holes 525 a-1 and 528through which the optical connectors 511 a-1 and 515 extend through. Thesingle printed circuit board may be mounted directly behind the frontpanel, so that the uni-wavelength interface indicators 523 a-1illuminate through the windows 513 a-1 of the front panel. FIG. 5Billustrates the process of moving the single printed circuit board 520behind the front panel 510, while FIG. 5C illustrates the single printedcircuit board 520 fully mounted behind the front panel 510, with theuni-wavelength interface indicators 523 a-1 illuminating through thewindows 513 a-1 of the front panel. In general, the uni-wavelengthinterface indicator for a given uni-wavelength interface is positionedclose to the optical connector of a given uni-wavelength interface suchthat it's visually apparent that the given uni-wavelength interfaceindicator is associated with the given connector.

The windows 513 a-1 consists of holes in the front panel and may furtherinclude glass or plastic covers or lenses covering the holes. There arealso larger holes in the front panel where the optical connectors 511a-1 are placed—one hole for each optical connector of eachuni-wavelength interface. The connectors 511 a-1 will have fiber opticalcables attached to them in order to attach to the multiplexing andde-multiplexing optics that sit behind the circuit board 520.

The multiplexer and demultiplexer circuit pack may optionally contain amulti-wavelength interface summary indicator 446 (associated withinterface 445) and 524 (associated with interface 515), wherein thesummary indicator indicates if there are connections between theuni-wavelength interfaces and any of the multi-wavelength interfaceswithin the node. When connections are made between the uni-wavelengthinterfaces and only a single multi-wavelength interface, the summaryindicator is illuminated with the color of the multi-wavelengthinterface indicator of the single multi-wavelength interface. Whenconnections are made between the uni-wavelength interfaces and a firstmulti-wavelength interface, and when connections are made between theuni-wavelength interfaces and at least a second multi-wavelengthinterface, the summary indicator cycles (sequences) through the colorsof the multi-wavelength interface indicators of the firstmulti-wavelength interface and the at least second multi-wavelengthinterface at a visible rate.

As shown in FIG. 4, the optical node 400 may additionally be comprisedof a plurality of transponder circuit packs 460 a-c. In theAdd-Direction, each transponder circuit pack is used to generate aspecific wavelength, that is then multiplexed with other wavelengths bythe circuit pack 440. In the Drop-Direction, each transponder takes in aspecific wavelength from the multiplexer and demultiplexer circuit pack,and converts the optical signal to an electrical format for furtherprocessing.

Each transponder additionally contains a service interface (not shown)that allows service data to be inputted into the node and removed fromthe node.

Each transponder 460 a-c attaches to a uni-wavelength interface 441 a-cof the multiplexer and demultiplexer circuit pack 440 via a pair ofoptical fibers that run from an optical connector on the transponder 462a-c to an optical connector on the uni-wavelength interface 441 a-c onthe multiplexer and demultiplexer circuit pack. Each transponder mayadditionally contain a uni-wavelength interface indicator 461 a-c,wherein the state of the uni-wavelength interface indicator on thetransponder matches the state of the uni-wavelength interface indicator443 a-c of the uni-wavelength interface that the transponder is attachedto on the multiplexer and demultiplexer circuit pack 440.

Each multi-color light source may be implemented with a multi-colorLight Emitting Diode (LED) or some other similar suitable light source.Alternatively, other technologies could be used to implement themulti-wavelength interface indicators. For instance, a single-digitalphanumeric display could be used to indicate multi-wavelengthinterfaces. In such an implementation each multi-wavelength interfacemay have a single-letter/digit alphanumeric display associated with it,and each uni-wavelength interface may have a single-letter/digitalphanumeric display associated with it. The alphanumeric display ofeach multi-wavelength interface would be illuminated with a specific anddistinct letter/number. When a connection is made between a givenuni-wavelength interface and a given multi-wavelength interface, theuni-wavelength interface indicator of the uni-wavelength interface wouldbe set to the letter/number of the multi-wavelength interface indicatorof the multi-wavelength interface that it is connected to.

Alternatively, an alphanumeric display with a plurality ofletters/digits could be utilized. For such an implementation, wholewords, such as EAST or WEST, or city names, such as Chicago or New York,could be displayed.

A multi-color LED used as an interface indicator may comprise at leasttwo co-located LEDs (i.e., two LED emitters) of different opticalwavelengths. Each of the at least two LEDs would generate a distinctvisible color when illuminated. An at least first and second LEDs may beco-packaged so that when both LEDs are illuminated the visible colors ofthe two LEDs mix together in such a way that the two LEDs appears to bea single light source. The co-packaged first and second LEDs could beused for all interface indicators. In order to indicate a firstmulti-wavelength interface, the first LED may be illuminated and thesecond LED may be extinguished. In order to indicate a secondmulti-wavelength interface, the second LED may be illuminated and thefirst LED may be extinguished. A third color could be used to indicate athird multi-wavelength interface by simultaneously illuminating bothLEDs in order to mix the colors of the first and second LEDs to create athird color.

Alternatively, a multi-color LED used as an interface indicator mayconsist of at least three co-packages LEDs (i.e., three LED emitters) ofdifferent optical wavelengths. If the first, second, and thirdco-packaged LEDs emit the three primary colors—red, green, and blue,respectively—then an additional number of colors can be created byilluminating certain combinations of the three LEDs simultaneously. Forinstance, the first LED may be illuminated and the second and third LEDsmay be extinguished in order to indicate a first multi-wavelengthinterface, and the second LED may be illuminated and the first and thirdLEDs may be extinguished in order to indicate a second multi-wavelengthinterface, and the second and third LEDs may be illuminated and thefirst LED may be extinguished in order to indicate a thirdmulti-wavelength interface. Alternatively, additional colors may beachieved by simultaneously mixing various intensities of the colors ofthe three LEDs. Various intensities can be achieved by varying thecurrent through the LEDs, or by using well known pulse width modulationtechniques.

Each multi-wavelength indicator may be assigned an additional statewhich may be used to indicate that there are no wavelengthstransitioning through the indicator's corresponding multi-wavelengthinterface (either to or from any uni-wavelength interfaces, or to andfrom any other multi-wavelength interfaces). This additional state maybe a specific color when multi-color indicators are used. Alternatively,the additional state could be indicated by turning off the indicator(e.g., no color). The additional state would be useful when performingmaintenance on multi-wavelength interfaces.

This invention further includes a method of indicating the connectionbetween interfaces. The method comprises indicating a first state with afirst interface indicator of a first interface, indicating a secondstate with a second interface indicator of a second interface, andindicating the first state and the second state with a third interfaceindicator of a third interface. Within the method, the third interfaceindicator indicates a connection between the third interface and thefirst interface by indicating the first state, and the third interfaceindicator indicates a connection between the third interface and thesecond interface by indicating the second state.

Within the method, the first and second interfaces may bemulti-wavelength interfaces, and the third interface may be auni-wavelength interface.

In the method, the first interface indicator may include a first lightemitting diode, and the second interface indicator may include a secondlight emitting diode, and the third interface indicator may include athird light emitting diode.

Alternatively, in the method, the first interface indicator may comprisea first alphanumeric display, and the second interface indicator maycomprise a second alphanumeric display, and the third interfaceindicator may comprise a third alphanumeric display.

Alternatively, in the method, the first interface indicator may includea first passive indicator, and the second interface indicator mayinclude a second passive indicator, and the third interface indicatormay include an active indicator of some type (multi-color oralphanumeric, for example).

Alternatively, in the method, the first interface indicator may compriseat least two light emitting diodes, and the second interface indicatormay comprise at least two light emitting diodes, and the third interfaceindicator may comprise at least two emitting diodes.

Within the method, the first state may be indicated by a first color andthe second state may be indicated by a second color.

Also, within the method, a connection between the third interface andthe first interface, and the third interface and the second interfacemay be indicated by the third interface indicator alternating betweenthe first state and the second state.

The invention may be extended to general interfaces within andapparatus. For this case, there may be an apparatus comprising a firstinterface with a first interface indicator capable of indicating a firststate. Additionally within the apparatus there may be a second interfacewith a second interface indicator capable of indicating a second state.Furthermore, within the apparatus there may be at least a thirdinterface with a third interface indicator capable of indicating thefirst state and the second state. Additionally, the apparatus maycontain a means for establishing connections between interfaces. Forsuch an apparatus, a connection between the at least third interface andthe first interface may be indicated by the third interface indicatorindicating the first state, and a connection between the at least thirdinterface and the second interface may be indicated by the thirdinterface indicator indicating the second state. The first and secondinterfaces may be multi-wavelength interfaces, and the third interfacemay be a uni-wavelength interface. The first interface indicator withinthis apparatus may include a first light emitting diode, and the secondinterface indicator may include a second light emitting diode, and thethird interface indicator may include a third light emitting diode.Alternatively, the first interface indicator may comprise a firstalphanumeric display, and the second interface indicator may comprise asecond alphanumeric display, and the third interface indicator maycomprise a third alphanumeric display. In yet another alternative, oradditionally, the first interface indicator may include a first passiveindicator, and the second interface indicator may include a secondpassive indicator, and the third interface indicator may include anactive indicator. Alternatively, the first interface indicator maycomprise at least two light emitting diodes, and the second interfaceindicator may comprise at least two light emitting diodes, and the thirdinterface indicator may comprise at least two emitting diodes. Withinthis apparatus, the first state may be indicated by a first color andthe second state may be indicated by a second color. Furthermore, aconnection between the at least third interface and the first interface,and the at least third interface the second interface may be indicatedby the third interface indicator alternating between the first state andthe second state. The apparatus may further comprise at least a fourthinterface with a fourth interface indicator capable of indicating athird state, wherein the third interface indicator may further becapable of indicating the third state, and wherein a connection betweenthe at least third interface and the first interface, and the at leastthird interface the second interface, and the at least third interfaceand the at least fourth interface may be indicated by the thirdinterface indicator sequencing from the first state, to the secondstate, to the third state, and back to the first state.

The invention may be simplified to apply to only two interfaces withinan apparatus. For this case, there may be an apparatus comprising afirst interface with a first interface indicator capable of indicating afirst state, and at least a second interface with a second interfaceindicator capable of indicating the first state and at least a secondstate. Additionally, the apparatus may contain a means for establishinga connection between the two interfaces. For such an apparatus, aconnection between the at least second interface and the first interfacemay be indicated by the second interface indicator indicating the firststate. When there is no connection between the at least second interfaceand the first interface the second interface indicator may indicate thesecond state. The first interface indicator within this apparatus mayinclude a first light emitting diode, and the second interface indicatormay include a second light emitting diode. Alternatively, the firstinterface indicator may comprise a first alphanumeric display, and thesecond interface indicator may comprise a second alphanumeric display.In yet another alternative, or additionally, the first interfaceindicator may include a first passive indicator, and the secondinterface indicator may include an active indicator. Alternatively, thefirst interface indicator may comprise at least two light emittingdiodes, and the second interface indicator may comprise at least twolight emitting diodes. Within this apparatus, the first state may beindicated by a first color and the second state may be indicated by asecond color. Alternatively, the first state may be indicated by a colorand the second state may be indicated by no color.

The invention may be simplified to apply to only two interfaces within amethod for indicating connections between interfaces. For this case, amethod for indicating connections between interfaces may compriseindicating a first state with a first interface indicator of a firstinterface, and indicating the first state and a second state with asecond interface indicator of a second interface. For this method, thesecond interface indicator may indicate a connection between the secondinterface and the first interface by indicating the first state, and thesecond interface indicator may indicate no connection between the firstinterface and the second interface by indicating the second state.Within the method, the first interface indicator may include a firstlight emitting diode and the second interface indicator may include asecond light emitting diode. Alternatively, the first interfaceindicator may comprise a first alphanumeric display, and the secondinterface indicator may comprise a second alphanumeric display.Additionally or alternatively, the first interface indicator may includea passive indicator, and the second interface indicator may include anactive indicator. Alternatively, the first interface indicator maycomprise at least two light emitting diodes, and the second interfaceindicator may comprise at least two light emitting diodes. Additionally,the first state may be indicated by a first color and the second statemay be indicated by a second color. In yet another alternative, thefirst state may be indicated by a color and the second state may beindicated by no color.

The optical node may be simplified such that the optical node comprisesa first optical interface, with a first interface indicator, and atleast a second optical interface, with a second interface indicator,wherein the first interface indicator and the second interface indicatorvisually indicate a connection between the first optical interface andthe second optical interface. Within this optical node, the firstinterface indicator may include a first light emitting diode, and thesecond interface indicator may include a second light emitting diode.Alternatively, the first interface indicator may comprise a firstalphanumeric display, and the second interface indicator may comprise asecond alphanumeric display. Additionally or alternatively, the firstinterface indicator may include a passive indicator, and the secondinterface indicator may include an active indicator. Additionally, thefirst interface indicator may comprise at least two light emittingdiodes, and the second interface indicator may comprise at least twolight emitting diodes. The optical node may further comprise at leastone ROADM circuit pack, wherein the ROADM circuit pack may comprise thefirst interface and the first interface indicator. The optical node mayfurther comprise at least one multiplexer and demultiplexer circuit packcomprising the at least second interface and the second interfaceindicator.

In the foregoing description, the invention is described with referenceto specific example embodiments thereof. It will, however, be evidentthat various modifications and changes may be made thereto withoutdeparting from the broader spirit and scope of the present invention.The specification and drawings are accordingly to be regarded in anillustrative rather than restrictive sense.

What is claimed is:
 1. An apparatus comprising: a first interface with afirst interface indicator, wherein the first interface indicatorcomprises of one Light Emitting Diode (LED) illuminating with a firstcolor; a second interface with a second interface indicator, wherein thesecond interface indicator comprises of one LED illuminating with asecond color, wherein the second color is different than the firstcolor; and a third interface with a third interface indicator, whereinthe third interface indicator comprises of one multi-color LED, whereinthe third interface indicator is operable to illuminate with the firstcolor to visually indicate a connection between the third interface andthe first interface, and wherein the third interface indicator isoperable to illuminate with the second color to visually indicate aconnection between the third interface and the second interface.
 2. Theapparatus of claim 1, wherein the first interface indicator comprises ofone multi-color LED, and the second interface indicator comprises of onemulti-color LED.
 3. The apparatus of claim 1, wherein the thirdinterface indicator is operable to illuminating with no color tovisually indicate that the third interface is not connected to the firstinterface and the third interface is not connected to the secondinterface.
 4. The apparatus of claim 1, wherein the third interfaceindicator is operable to illuminating with a third color to visuallyindicate that the third interface is not connected to the firstinterface and the third interface is not connected to the secondinterface.
 5. The apparatus of claim 1, wherein to visually indicate aconnection between the third interface and the first interface and aconnection between the third interface and the second interface, thethird interface indicator is operable to alternate between illuminatingwith the first color and the second color.
 6. The apparatus of claim 1,further comprising a fourth interface with a fourth interface indicator,wherein the fourth interface indicator comprises of one LED illuminatingwith a third color, wherein the third color is different than the firstcolor and the second color, and wherein to visually indicate aconnection between the third interface and the first interface and aconnection between the third interface and the second interface and aconnection between the third interface and the fourth interface, thethird interface indicator is operable to cycle through illuminating withthe first color and the second color and the third color.
 7. Theapparatus of claim 1, wherein the first interface indicator ispositioned close to the first interface to visually indicate that thefirst interface indicator is associated with the first interface, andthe second interface indicator is positioned close to the secondinterface to visually indicate that the second interface indicator isassociated with the second interface, and the third interface indicatoris positioned close to the third interface to visually indicate that thethird interface indicator is associated with the third interface.
 8. Theapparatus of claim 1, further comprising at least a fourth interfacewith a fourth interface indicator, wherein the fourth interfaceindicator comprises of one multi-color LED, and wherein the fourthinterface indicator is operable to illuminate with the first color tovisually indicate a connection between the fourth interface and thefirst interface, and wherein the fourth interface indicator is operableto illuminate with the second color to visually indicate a connectionbetween the fourth interface and the second interface.
 9. The apparatusof claim 1, further comprising: a front panel with a connector for thethird interface; and a printed circuit board comprising the thirdinterface indicator and a hole for the connector to extend through. 10.A method for visually indicating connections between interfacescomprising: configuring a first indicator of a first interface with afirst color; configuring a second indicator of a second interface with asecond color, wherein the second color is different than the firstcolor; configuring a third indicator of a third interface with the firstcolor when connecting the third interface to the first interface; andconfiguring the third indicator with the second color when connectingthe third interface to the second interface.
 11. The method of claim 10,wherein the first interface is a first multi-wavelength interface, andsecond interface is a second multi-wavelength interface, and the thirdinterface is a uni-wavelength interface.
 12. The method of claim 10,further comprising configuring the third indicator to alternate betweenthe first color and the second color when connecting the third interfaceto the first interface and the second interface.
 13. An optical nodeproviding a visual indication of connections between interfacescomprising: a first multi-wavelength interface with a firstmulti-wavelength interface indicator illuminating with a first color; asecond multi-wavelength interface with a second multi-wavelengthinterface indicator illuminating with a second color, wherein the secondcolor is different from the first color; and a uni-wavelength interfacewith a uni-wavelength interface indicator, wherein the uni-wavelengthinterface indicator is operable to illuminate with the first color whenthe uni-wavelength interface is connected to the first multi-wavelengthinterface, and wherein the uni-wavelength interface indicator isoperable to illuminate with the second color when the uni-wavelengthinterface is connected to the second multi-wavelength interface.
 14. Theoptical node of claim 13, wherein the optical node is operable toestablishing an inter-node connection between the uni-wavelengthinterface and a second uni-wavelength interface of a second optical nodethrough the first multi-wavelength interface, and wherein theuni-wavelength interface indicator is operable to alternate betweenilluminating with the first color and no color when there is a problemwith the inter-node connection.
 15. The optical node of claim 13,wherein the optical node is operable to establishing a first inter-nodeconnection between the uni-wavelength interface and a seconduni-wavelength interface of a second optical node through the firstmulti-wavelength interface, and wherein the optical node is operable toestablishing a second inter-node connection between the uni-wavelengthinterface and a third uni-wavelength interface of a third optical nodethrough the second multi-wavelength interface, wherein theuni-wavelength interface indicator is operable to alternate betweenilluminating with the first color during a first time period and thesecond color during a second time period to indicate the firstinter-node connection and the second inter-node connection.
 16. Theoptical node of claim 15, wherein the uni-wavelength interface indicatoris operable to alternate between illuminating with the first color andno color during the first time period to indicate a problem with thefirst inter-node connection, and wherein the uni-wavelength interfaceindicator is operable to alternate between illuminating with the secondcolor and no color during the second time period to indicate a problemwith the second inter-node connection.
 17. The optical node of claim 13,further comprising at least one ROADM circuit pack comprising the firstmulti-wavelength interface, the second multi-wavelength interface, thefirst multi-wavelength interface indicator, and the secondmulti-wavelength interface indicator.
 18. The optical node of claim 17,further comprising a multiplexer and demultiplexer circuit packcomprising the uni-wavelength interface and the uni-wavelength interfaceindicator.
 19. The optical node of claim 18, wherein the multiplexer anddemultiplexer circuit pack further comprises: a second uni-wavelengthinterface with a second uni-wavelength interface indicator; and a thirdmulti-wavelength interface with a multi-wavelength interface summaryindicator, wherein the third multi-wavelength interface is used toconnect the multiplexer and demultiplexer circuit pack to the ROADMcircuit pack, and wherein the multi-wavelength interface summaryindicator is operable to illuminate with the first color when theuni-wavelength interface is connected to the first multi-wavelengthinterface and the second uni-wavelength interface is connected to thefirst multi-wavelength interface, and wherein the multi-wavelengthinterface summary indicator is operable to illuminate with the secondcolor when the uni-wavelength interface is connected to the secondmulti-wavelength interface and the second uni-wavelength interface isconnected to the second multi-wavelength interface, and wherein themulti-wavelength interface summary indicator is operable to alternatebetween illuminating with the first color and illuminating with thesecond color when the uni-wavelength interface is connected to the firstmulti-wavelength interface and the second uni-wavelength interface isconnected to the second multi-wavelength interface.
 20. The optical nodeof claim 18, wherein the multiplexer and demultiplexer circuit packfurther comprises: a front panel with an optical connector for theuni-wavelength interface; and a printed circuit board comprising theuni-wavelength interface indicator and a hole for the optical connectorto extend through.